Photonic optoelectronic module packaging

ABSTRACT

In one example, an optoelectronic module may include a stack assembly including an electrical integrated circuit and an optical integrated circuit electrically and mechanically coupled to one another, an interposer electrically and mechanically coupled to the stack assembly, and an optical connector to optically couple the optical integrated circuit with an array of optical fibers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/887,349 filed Aug. 15, 2019, titled FLIP CHIPFACE TO FACE DIE-STACKED INTEGRATED SILICON PHOTONIC OPTOELECTRONICMODULE PACKAGING, which is incorporated herein by reference in itsentirety.

BACKGROUND

Unless otherwise indicated herein, the materials described herein arenot prior art to the claims in the present application and are notadmitted to be prior art by inclusion in this section.

The present disclosure generally relates to assembly and packagingconfigurations for optoelectronic modules.

Optoelectronic modules, such as transceivers, are increasingly used totransmit data between different devices or different locations. Inparticular, optical signals maybe used to rapidly communicate data (viathe optical signals) between different devices or different locations.However, most electronic devices operate using electrical signals.Accordingly, optoelectronic modules may be used to convert opticalsignals to electrical signals and/or convert electrical signals tooptical electrical, so optical signals may be used to transmit databetween electronic devices. Optoelectronic modules may communicate witha host device by transmitting electrical signals to the host device andreceiving electrical signals from the host device. These electricalsignals may then be transmitted by the optoelectronic module as opticalsignals.

The subject matter claimed herein is not limited to implementations thatsolve any disadvantages or that operate only in environments such asthose described above. Rather, this background is only provided toillustrate one example technology area where some implementationsdescribed herein may be practiced.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential characteristics of the claimed subject matter, nor is itintended to be used as an aid in determining the scope of the claimedsubject matter.

The present disclosure generally relates to assembly and packagingconfigurations for optoelectronic modules.

In one non-limiting example, an optoelectronic module may include astack assembly including an electrical integrated circuit and an opticalintegrated circuit electrically and mechanically coupled to one another,an interposer electrically and mechanically coupled to the stackassembly, and an optical connector to optically couple the opticalintegrated circuit with an array of optical fibers. The interposer maydefine a recess and the electrical integrated circuit of the stackassembly may be positioned at least partially within the recess.

In another example, a method may include face to face bonding anelectrical integrated circuit and an optical integrated circuit to oneanother to form a stack assembly. The method may include flip-chipbonding the stack assembly to an interposer. The method may includeoptically coupling the optical integrated circuit with a fiber array viaan optical connector. The method may include mechanically coupling theoptical connector to the interposer.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by the practice of the invention. Thefeatures and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other features will become more fullyapparent from the following description and appended claims, or may belearned by the practice as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a perspective view of an example optoelectronic module.

FIGS. 2A-2F are perspective views of another example of anoptoelectronic module.

FIG. 3 is a perspective view of an example multiple chip module that mayinclude the optoelectronic module of FIGS. 2A-2F.

FIG. 4 is a schematic view of another example of a multiple chip moduleassembly.

FIG. 5 is a schematic view of another example of a multiple chip moduleassembly.

FIGS. 6A-6B are side cross-sectional views of examples optoelectronicmodules.

FIG. 7 is a perspective view of another example of an optoelectronicmodule.

DETAILED DESCRIPTION

The present disclosure generally relates to assembly and packagingconfigurations for optoelectronic modules.

Optoelectronic modules, such as transceivers, are increasingly used totransmit data between different devices or different locations. Inparticular, optical signals maybe used to rapidly communicate data (viathe optical signals) between different devices or different locations.However, most electronic devices operate using electrical signals.Accordingly, optoelectronic modules may be used to convert opticalsignals to electrical signals and/or convert electrical signals tooptical signals, so optical signals may be used to transmit data betweenelectronic devices. Optoelectronic modules may communicate with a hostdevice by transmitting electrical signals to the host device andreceiving electrical signals from the host device. These electricalsignals may then be transmitted by the optoelectronic module as opticalsignals.

Optoelectronic modules may be implemented in optical networks used tocommunicate optical signals for transmitting information among variousnodes of a telecommunications network. To transmit data in an opticalnetwork, the data may be converted from an electrical signal to anoptical signal using optoelectronic components, or vice versa. Opticalnetworks are one example of an environment where the optoelectronicmodules devices described herein may be implemented. However, theconcepts described may also be implemented in other circumstances. Forexample, optoelectronic modules may be implemented in computerprocessing, sensors, optical routing, signal processing or othersuitable applications. The embodiments disclosed herein are not limitedto any specific environment unless indicated by context.

Some optoelectronic modules include multiple integrated circuits toperform various tasks, and in some configurations, optoelectronicmodules may include both electrical integrated circuits and opticalintegrated circuits. One difficulty with the inclusion of multipleintegrated circuits is positioning many different components in arelatively small area. As the density of components increases,components may be positioned closer to one another, as well asconnections coupling them together (e.g., electrical or opticalconnections). Accordingly, designing and manufacturing higher densityoptoelectronic assemblies and/or optoelectronic modules may lead tovarious challenges, such as signal integrity, power integrity, thermalperformance, electrical coupling and optical coupling.

In some optoelectronic assemblies, silicon photonics may be implementedfor optical or optoelectronic components. For example, silicon photonicsmay be implemented as optical integrated circuits. Silicon photonicsgenerally involve the use of silicon as an optical medium for optical oroptoelectronic devices. In some photonics devices, the silicon may bepositioned on top of a layer of silicon, such configurations are knownas silicon on insulator (SOI). The silicon may be patterned intophotonic components or micro-photonic components. Silicon photonicdevices may be made using existing semiconductor fabrication techniques,and because silicon is already used as the substrate for some integratedcircuits, it may be possible to create hybrid devices in which theoptical and electronic components are integrated onto a single microchipor in single assemblies.

Various assembly and packaging configurations are implemented inmanufacturing optoelectronic assemblies. One example is flip chipoptoelectronic assemblies, which interconnect components using solderbumps that have been deposited onto pads. In flip chip configurations,solder bumps may be deposited on pads on a top side of a firstcomponent, the first component may be flipped over so that its top sidefaces down, and aligned so that its pads align with matching pads on asecond component. The first and second components may be mechanicallyand electrically coupled to one another by solder reflow, such that thepads of the first and second components are attached to one another bythe solder bumps. Flip chip configurations may be contrasted with wirebonding configurations, which typically have two components which areboth mounted upright, one on top of another, with pads on top of bothcomponents, and wires used to electrically couple the pads.

The disclosed embodiments include assembly and packaging configurationsfor optoelectronic modules with flip chip face-to-face die-stackedintegrated silicon photonics. Face to face die stacking may permitheterogeneous integration of photonic circuits (e.g., optical assembliesor optical integrated circuits) and electronic circuits (e.g.,electrical assemblies or electrical integrated circuits) for highbandwidth density optoelectronic assemblies, such as those that may beimplemented in fiber optic transceivers.

Such configurations may be implemented in any suitable optoelectronicmodules, however, the configurations may be particularly advantageous incompact form-factor optoelectronic modules to address the challenges ofco-packaging silicon photonics optics with electronic components, suchas application-specific integrated circuits (ASICs), Field-programmablegate arrays (FPGAs), central processing units (CPUs) microprocessors, orother electronic components that may be implemented in optoelectronicmodules.

The disclosed configurations for highly integrated photonicoptoelectronic assembly packaging may eliminate wire bonds, improvemechanical integrity, improve power and signal integrity, and providesuperior thermal performance. Additionally or alternatively, thedisclosed embodiments may support the use of land grid array (LGA) orball grid array (BGA) packaging or sockets. Further, the disclosedembodiments may facilitate high yield assembly of optical components,such as optical inputs and outputs, which may be co-packaged withelectronic components (e.g., ASICs, FPGAs, CPUs, etc.).

Reference will now be made to the drawings and specific language will beused to describe various aspects of the disclosure. Using the drawingsand description in this manner should not be construed as limiting itsscope. Additional aspects may be apparent in light of the disclosure,including the claims, or may be learned by practice.

FIG. 1 is a perspective view of an example optoelectronic module 100.The optoelectronic module 100 may include an interposer 102 and a stackassembly 104. The stack assembly 104 may include integrated circuits(ICs), such as an electrical integrated circuit (EIC) 106 and an opticalintegrated circuit (OIC) 108. The OIC 108 may include various integratedoptical components for detecting, focusing, and/or modulating opticalsignals. In some configurations, the OIC 108 may be a photonic circuitor an integrated silicon photonic circuit. The EIC 106 may includevarious electrical components for transmitting, processing, and/ormodulating electrical signals. Additionally, the EIC 106 and the OIC 108may include optoelectronic components to convert optical signals toelectrical signals, convert electrical signals to optical signals, orboth.

Such optoelectronic components may include optical transmitters, and/oroptical receivers. Additional components may include integrated circuitsthat perform other physical layer functions such as retiming, forwarderror correction and equalization. Optical transmitters may be assembledfrom such components as lasers, laser drivers, modulators, waveguides,gratings, wavelength division multiplexers, splitters, alignmentstructures and coupling structures. Optical receivers may contain suchcomponents as photodiodes, transimpedance amplifiers, waveguides,polarization splitters/combiners/rotators, gratings, wavelength divisiondemultiplexers, and alignment and coupling structures. In someconfigurations, the optoelectronic components may be arranged as arrays,such as receiver arrays and/or transmitter arrays. Accordingly, in someconfigurations, the optoelectronic module 100 may be an optical engine.The OIC 108 may include photodiodes integrated with the OIC 108. In someaspects the photodiodes may be germanium photodiodes integrated with theOIC 108. In other aspects, lasers may be optically coupled to OIC 108through a fiber array via an optical connecter.

In the configuration shown in FIG. 1 , the lasers may be positionedoutside the optoelectronic module 100 and therefore not shown. Lightfrom the lasers may be coupled to the OIC 108 through a fiber array viaan optical connector. However, in other configurations the lasers may bebonded to the OIC 108 proximate the EIC 106. The photodiodes may beintegrated components on the OIC 108. In some aspects, the photodiodesmay be part of the OIC 108, which may include many other componentsincluding the modulators, waveguides, splitters, etc.

The interposer 102 may provide mechanical support to the stack assembly104 when the components are attached to one another. Furthermore, theinterposer 102 may electrically couple the stack assembly 104.Accordingly, the interposer 102 may include electrical couplings 112 tobe coupled to the stack assembly 104. Similarly, the stack assembly 104may include electrical couplings 114 to be coupled to the interposer102. As shown, the electrical couplings 112 of the interposer 102 maycorrespond to the electrical couplings 114 of the stack assembly 104.The size, position and arrangement of the electrical couplings 112, 114may be complimentary to permit them to be coupled to one another. Asshown, the electrical couplings 112 may be positioned on a top surfaceof the interposer 102, and the electrical couplings 114 may bepositioned on a top surface of the OIC 108.

The stack assembly 104 may be flip-chip bonded to the interposer 102. Insuch configurations, the interposer 102 may include a recess 110 sizedand shaped to receive the EIC 106 of the stack assembly 104. The stackassembly 104 may be flipped to position the electrical couplings 114 toface the electrical couplings 112 of the interposer 102, which may thenbe positioned against one another, and then coupled to one another. Theelectrical couplings 112, 114 may be coupled to one another by anysuitable process, for example, by melting solder positioned between theelectrical couplings 112, 114, using a technique such as mass reflow.When assembled, the EIC 106 may be partially or fully received in therecess 110 of the interposer 102. In some circumstances, the EIC 106 maybe positioned against an interior surface of the interposer 102 thatdefines the recess 110, thereby providing mechanical support for the EIC106.

The optoelectronic module 100 may include an optical connector 116 tooptically couple the OIC 108 with optical fibers. In someconfigurations, the optical connector 116 may optically couple the OIC108 to an array of optical fibers. The optical connector 116 may beincluded in the interposer 102 or they may be separate components. Ifthe optical connector 116 and the interposer 102 are separatecomponents, the interposer 102 and the optical connector 116 may becoupled to one another.

As shown, the EIC 106 and the OIC 108 may be coupled to one another toform the stack assembly 104. In such configurations, the stack assembly104 may be a silicon photonic stacked die. The EIC 106 may be referredto as a daughter or top die, and the OIC 108 may be referred to as amother or bottom die. The EIC 106 and the OIC 108 may be assembled orbonded face to face (F2F) with respect to one another, and may becoupled using fine pitch copper pillars or other suitable mechanicaland/or electrical couplings. The electrical couplings may be formedusing thermal compression bonding or mass reflow.

Although any suitable configuration may be implemented, in someconfigurations the electrical couplings 112, 114 may include copper (Cu)pillars or C4 balls, the interposer 102 may include a ceramic or othersuitable substrate material, and the optical connector 116 may includeglass, silicon, or any other suitable transparent material fortransmitting optical signals. In some configurations, the electricalcouplings 112, 114 that couple the stack assembly 104 to the interposer102 may be larger in diameter and/or pitch than the electrical couplingsthat couple the EIC 106 and the OIC 108.

As mentioned, the optical connector 116 may be coupled to the interposer102. In such configurations, the interposer 102 may include a windowand/or recess to receive the optical connector 116 and/or other opticalcomponents. The window and/or recess may permit a silicon photonicadiabatic mode converter or grating coupler to be exposed to align theoptical connector 116 with a fiber array. In such configurations, theoptoelectronic module 100 may be powered up to optically align theoptical components to one another.

FIGS. 2A-2F are perspective views of another example of anoptoelectronic module 200. The optoelectronic module 200 may include anysuitable aspects described above with respect to the optoelectronicmodule 100, although some features may have differing configurations,and some components, such as the electrical couplings, are not shown.

The optoelectronic module 200 may include an interposer 202 and a stackassembly 204. The stack assembly 204 may include ICs, such as an EIC 206and an OIC 208. The OIC 208 may include various integrated opticalcomponents for directing, focusing, and/or modulating optical signals.In some configurations, the OIC 208 may be a photonic circuit or anintegrated silicon photonic circuit. The EIC 206 may include variouselectrical components for transmitting, processing, and/or modulatingelectrical signals. Additionally, either the EIC 206 or the OIC 208 mayinclude optoelectronic components to convert optical signals toelectrical signals, convert electrical signals to optical signals, orboth. In some configurations, the optoelectronic module 200 may be anoptical engine.

Such optoelectronic components may include optical transmitters, and/oroptical receivers. Additional components may include integrated circuitsthat perform other physical layer functions such as retiming, forwarderror correction and equalization. Optical transmitters may be assembledfrom such components as lasers, laser drivers, modulators, waveguides,gratings, wavelength division multiplexers, splitters, alignmentstructures and coupling structures. Optical receivers may contain suchcomponents as photodiodes, transimpedance amplifiers, waveguides,polarization splitters/combiners/rotators, gratings, wavelength divisiondemultiplexers, and alignment and coupling structures. In someconfigurations, the optoelectronic components may be arranged as arrays,such as receiver arrays and/or transmitter arrays. Accordingly, in someconfigurations, the optoelectronic module 100 may be an optical engine.The OIC 208 may include photodiodes integrated with the OIC 208. In someaspects the photodiodes may be germanium photodiodes integrated with theOIC 208. In other aspects, lasers may be optically coupled to OIC 208through a fiber array.

The interposer 202 may provide mechanical support to the stack assembly204 when the components are attached to one another. Furthermore, theinterposer 202 may electrically couple the stack assembly 204. Althoughnot shown, the interposer 202 and the stack assembly 204 may includeelectrical coupling as described with respect to FIG. 1 .

The interposer 202 may include a recess 210 sized and shaped to receivethe EIC 206 of the stack assembly 204. The EIC 206 may be partially orfully received in the recess 210 of the interposer 202 (see, e.g., FIGS.2A and 2B).

The optoelectronic module 200 may include an optical connector 216 tooptically couple the OIC 208 with optical fibers 222. In someconfigurations, the optical fibers 222 may be an array of opticalfibers, for example, in a linear configuration, although otherconfigurations may be implemented. As shown, the optical connector 216and the interposer 202 may be separate components coupled to oneanother.

The optical connector 216 may include a body 228, which may include ormay be formed of a transparent substrate, such as glass, silicon, orother suitable transparent material. The body 228 may define grooves,slots or openings sized and shaped to receive the optical fibers 222.The position of the grooves, slots or openings may correspond to theposition of the optical fibers 222 in the fiber array. In someconfigurations, the optical connector 216 may include grooves, slots oropenings for each corresponding one of the optical fibers 222, althoughother configurations may be implemented.

The optoelectronic module 200 may include an adiabatic mode converter(AMC) 220. The AMC 220 may optically couple OIC 208 and the opticalconnector 216, which may be optically coupled to the optical fibers 222.The AMC 220 may be also be mechanically coupled to the OIC 208 to serveas an interface block between the optical connector 216, the opticalfibers 222, and the OIC 208. In some configurations, the OIC 208 mayinclude a silicon photonic integrated circuit, and the AMC 220 mayinclude silicon nitride adiabatic couplers to optically couple the OIC208 with the optical connector 216 and/or the optical fibers 222. Anexample of such aspects is included in U.S. Pat. No. 9,874,691, which ishereby incorporated by reference in its entirety.

As shown, the interposer 202 may include a recess 218 sized and shapedto receive the AMC 220 and/or a portion of the optical connector 216.The recess 218 may permit the AMC 220 to be aligned with the opticalconnector 216 and/or the OIC 208.

The optoelectronic module 200 may include one or more alignment featuresto align the optical connector 216, the AMC 220 and/or the interposer202 with one another. In the illustrated example, the optical connector216 includes alignment features 224 to align the optical connector 216with the interposer 202. The interposer 202 includes alignment features226 corresponding to the alignment features 224 of the optical connector216. The alignment features 224, 226 may permit the optical connector216 and the interposer 202 to be aligned and/or coupled to one another.In particular, the alignment features 224, 226 may permit the opticalconnector 216 to be moved with respect to the interposer 202 in onedirection (or vice versa, where the interposer 202 may be moved withrespect to the optical connector 216), while restricting movement inother directions.

In the illustrated configuration, the alignment features 224 are pins(e.g., round pins) attached to the optical connector 216 and thealignment features 226 are corresponding holes defined in the body ofthe interposer 202. In particular, the pins of the optical connector 216are sized and shaped to mate with and be received in corresponding holesof the interposer 202. However, this configuration is just one exampleof mating alignment features. Any other suitable mating alignmentfeatures may be implemented on the optical connector 216 and theinterposer 202. In addition, although the pin and hole configuration ofthe alignment features 224, 226 restrict movement in two directions(e.g., X and Y) while permitting movement in a third direction (e.g, Z),other configurations may be implemented that permit additional range ofmotion. For example, slots or rips may be implemented to permit movementin two direction (e.g., Z and X) while restricting movement in onedirection (e.g., Y). In some circumstances, the optoelectronic module200 may be powered up to optically align the optical components to oneanother.

FIGS. 2A-2F illustrate an example of an assembly process for theoptoelectronic module 200. With attention to FIGS. 2A-2F, aspects ofassembling the optoelectronic module 200 will be described in furtherdetail.

As shown in FIG. 2A, the EIC 206 and the OIC 208 may be coupled to oneanother to form the stack assembly 204. In such configurations, thestack assembly 204 may be a silicon photonic stacked die. The EIC 206may be referred to as a daughter or top die, and the OIC 208 may bereferred to as a mother or bottom die. The EIC 206 and the OIC 208 maybe assembled or bonded face to face (F2F) with respect to one another,and may be coupled using fine pitch copper pillars or other suitablemechanical and/or electrical couplings. The electrical couplings may beformed using thermal compression bonding or mass reflow. In someconfigurations, the electrical couplings that couple the stack assembly204 to the interposer 202 may be larger in diameter and/or pitch thanthe electrical couplings that couple the EIC 206 and the OIC 208 to oneanother.

The stack assembly 204 may be flip-chip bonded to the interposer 202, orvice versa. As indicated by arrow 250, the stack assembly 204 may beflipped such that the EIC 206 is facing the interposer 202. The stackassembly 204 and the interposer 202 may be positioned against oneanother, and then electrically and mechanically coupled. Although notshown, electrical couplings of the OIC 208 may be positioned to face theelectrical couplings of the interposer 202, which may then be positionedagainst one another, and then coupled to one another. The electricalcouplings may be coupled to one another by any suitable process, forexample, by melting solder positioned between the electrical couplingsusing a technique such as mass reflow. When assembled, the EIC 206 maybe partially or fully received in the recess 210 of the interposer 202.Additionally or alternatively, the EIC 206 may be positioned against aninterior surface inside the recess 210.

FIG. 2B shows the stack assembly 204 flip chip bonded to the interposer202, as described above. While FIG. 2B illustrates a top perspectiveview of the optoelectronic module 200, FIG. 2C illustrates a bottomperspective view of the optoelectronic module 200. As indicated by arrow252 in FIG. 2C, the optoelectronic module 200 may be flipped over, forexample, after the stack assembly 204 is flip-chip bonded to theinterposer 202. As shown, the interposer 202 may include electricalcouplings 230 to electrically couple the interposer 202.

As indicated by the arrow 254, the AMC 220 may be positioned in therecess 218 defined by the interposer 202. As shown, the recess 218exposes a portion of the OIC 208. The AMC 220 may be optically and/ormechanically coupled to the OIC 208 at the portion exposed by the recess218 defined by the interposer 202. In some configurations, the AMC 220may be attached directly to the OIC 208, without being coupled to theinterposer 202, although other configurations may be implemented. TheAMC 220 may be positioned against one or both of the interposer 202and/or the OIC 208.

FIG. 2D shows the AMC 220 positioned in the recess 218 and coupled tothe OIC 208. As shown, when the AMC 220 positioned in the recess 218, aportion of the recess 218 remains to receive a portion of the opticalconnector 216. In such configurations, the recess 218 may be sized andshaped to receive both the AMC 220 and a portion of the opticalconnector 216.

As indicated by the arrow 256, the optical connector 216 may be coupledto the interposer 202, with the AMC 220 positioned in between. A portionof the optical connector 216 may be positioned at least partially in therecess 218. The corresponding alignment features 224, 226 may bepositioned to mate with one another. In the illustrated configuration,the pins of the alignment features 224 are positioned inside of theholes of the alignment features 226, although other configurations maybe implemented. The optical connector 216 may be positioned against theAMC 220 and the interposer 202, and the components may be coupled to oneanother.

FIG. 2E shows the optical connector 216 coupled to the interposer 202with the AMC 220 positioned in between. In such configurations, the AMC220 may optically couple the optical fibers 222 of the optical connector216 with the OIC 208. Furthermore, the optical connector 216, theoptical fibers 222, the AMC 220, and/or the OIC 208 may be optically andmechanically aligned with one another.

While FIG. 2E illustrates a bottom perspective view of theoptoelectronic module 200, FIG. 2F illustrates a top perspective view ofthe optoelectronic module 200. As indicated by arrow 258 in FIG. 2F, theoptoelectronic module 200 may be flipped over, for example, after theoptical connector 216 is coupled to the interposer 202. Theoptoelectronic module 200 may then be coupled to other components, aswill be described in further detail below.

FIG. 3 is a perspective view of an example multiple chip module (MCM)300. The MCM 300 may be implemented to removably co-package multipleoptoelectronic modules and/or optical interconnects for optical fibers.The MCM 300 may include a substrate 302 and one or more sockets 304,which may be positioned on the substrate 302. The sockets 304 may eachremovably receive an optoelectronic module. Furthermore, the sockets 304may electrically and mechanically couple optoelectronic modules to theMCM 300. Accordingly, the sockets 304 may include electrical couplings306 to electrically couple with the optoelectronic modules, fasteners308 to mechanically couple the optoelectronic modules to the MCM 300,and receptacles 310 sized and shaped to receive the optoelectronicmodules. In FIG. 3 , the electrical couplings 306, fasteners 308, andreceptacle 310 are labeled for one of the sockets 304, although each ofthe sockets 304 may include such features.

In the illustrated configuration, each of the sockets 304 includes threeof the fasteners 308, however, any suitable number and configuration offasteners may be implemented. The fasteners 308 may removably couple theoptoelectronic modules to the MCM 300. In the illustrated configuration,the fasteners 308 are resilient tabs that may be spread apart to permitthe optoelectronic modules to be inserted and retained in thereceptacles 310. However, other configurations of the fasteners 308 maybe implemented. The fasteners 308 may be spread apart to permit theoptoelectronic modules to be removed from the receptacles 310.Accordingly, the fasteners 308 may removably retain the optoelectronicmodules in the fasteners.

As mentioned above, the sockets 304 of the MCM 300 may receiveoptoelectronic modules, such as the optoelectronic module 200 of FIGS.2A-2F. FIG. 3 illustrates the optoelectronic module 200 positioned overone of the sockets 304. The optoelectronic module 200 may be positionedin the receptacle 310 of the socket 304. As shown, the receptacle 3310is sized and shaped to receive the optoelectronic module 200. Theelectrical couplings 306 of the socket 304 may correspond to theelectrical couplings 230 of the optoelectronic module 200 (see, forexample, FIG. 2E). The electrical couplings 230 may be positionedagainst the electrical couplings 306 to electrically couple theoptoelectronic module 200 to the MCM 300. The fasteners 308 mayremovably retain the optoelectronic module 200 in the receptacle 310.Accordingly, the fasteners 308 may be sized and positioned to at leastpartially surround the optoelectronic module 200 to retain theoptoelectronic module 200 in the receptacle 310. Specifically, thefasteners 308 may be positioned against and at least partially surroundthe interposer 202 and/or the stack assembly 204 of the optoelectronicmodule 200. Although FIG. 3 illustrates one optoelectronic module 200,corresponding optoelectronic modules may be positioned in each of thesocket 304 of the MCM 300.

As shown, the socket 304 defines a perimeter corresponding to the sizeand shape of the optoelectronic module 200. The perimeter includes arecess 312 sized and shaped to permit the optical connector 216 and/orthe optical fibers 222 to extend out of the socket 304. Suchconfigurations permit the optoelectronic module 200 to be opticallycoupled with components outside of the MCM 300.

The MCM 300 may include an IC 314. The IC 314 may be a switch ASIC,FPGA, CPUs, etc. The IC 314 may be electrically coupled to theoptoelectronic modules attached to the MCM 300 via the electricalcouplings 306. The IC 314 may route electrical signals to theoptoelectronic modules. As mentioned, the optoelectronic module 200 maybe an optical engine. Accordingly, in the configurations shown in FIG. 3, eight optoelectronic modules or optical engines may be co-packaged onthe MCM 300. The optical engines may be electrically interfaced with theIC 314 and optically interfaced with optical fibers extending from theMCM 300. In some configurations, the optical engines may include LGApackaging and/or the MCM 300 may include corresponding LGA sockets. Suchconfigurations may be implemented for high speed LGA socket interfaceswith the adjacent IC 314 (which may be a switch circuit).

The MCM 300 may include various optoelectronic modules withoptoelectronic components that covert electrical signals to opticalsignals, or vice versa. However, in other configurations, theoptoelectronic components may be included separate of the MCM 300. Insuch configurations, the modules may include optical components, ratherthan optoelectronic components. FIG. 4 illustrates an example of such aconfiguration.

FIG. 4 is a schematic view of an example of an MCM assembly 400. Asillustrated, the MCM assembly 400 may include an MCM 410 with opticalchips 402. The optical chips 402 may be positioned on the MCM 410, in amanner similar to the configuration shown and described with respect toFIG. 3 . However, rather than including optoelectronic components on theoptical chips 402, the optoelectronic components may be included in anexternal optoelectronic assembly 404. The optoelectronic assembly 404may include optoelectronic components 406. The optoelectronic components406 may be optical transmitters such as lasers, or optical receiverssuch as photodiodes. In the illustrated configuration, theoptoelectronic assembly 404 includes eight optoelectronic components406, one for each of the optical chips 402.

As indicated, each of the optoelectronic components 406 are opticallycoupled with a corresponding one of the optical chips 402. Theoptoelectronic components 406 and the optical chips 402 may be opticallycoupled to one another with a fiber or other suitable optical coupling.In some configurations, the optoelectronic components 406 may generateoptical signals, which may be transmitted and/or modulated by theoptical chips 402, to optical fibers coupled to the optical chips 402.In other configurations, the optoelectronic components 406 may receiveoptical signals, which may be transmitted and/or modulated by theoptical chips 402 from the optical fibers.

The configurations shown in FIG. 4 may provide optical transmittersand/or optical receivers off-chip with respect to the MCM 410 and theoptical chips 402. In some aspects, the optoelectronic components 406may be lasers and the optoelectronic assembly 404 may be a laser bank.The laser bank may be mounted and cooled separately from the MCM 410 andthe optical chips 402. Such configurations may improve efficiency andreliability of the MCM 410 and associated MCM assembly 400. Each of theoptoelectronic components 406 may include one or more lasers and maypower one of the optical chips 402 via a polarization maintaining (PM)fiber array. Furthermore, the optoelectronic components 406 may beremovable laser modules to further improve serviceability and/orreliability.

FIG. 5 is a schematic view of another example of an MCM assembly 500. Asillustrated, the MCM assembly 500 may include an MCM 510 with opticalchips 502. The optical chips 502 may be positioned on the MCM 510.Rather than including optoelectronic components on an externaloptoelectronic assembly (as described with respect to FIG. 4 ), the MCMassembly 500 may include optoelectronic components 506 removably coupledto a switch box faceplate 508 of the MCM assembly 500. Theoptoelectronic components 506 may be optical transmitters such aslasers, or optical receivers such as photodiodes. In the illustratedconfiguration, the MCM assembly 500 includes eight optoelectroniccomponents 506, one for each of the optical chips 502. Each of theoptoelectronic components 506 may be optically coupled with acorresponding one of the optical chips 502.

The configurations shown in FIG. 5 , which includes the optoelectroniccomponents 506 removably coupled to the switch box faceplate 508, mayimprove reliability and serviceability of the MCM assembly 500, becausethe optoelectronic components 506 may be removed and replaced as needed.

In some aspects, the optoelectronic components 506 may be lasers, forexample, pluggable laser modules removably attached to the switch boxfaceplate 508. In some configurations, the laser modules maybe attachedto the MCM assembly 500 after the MCM assembly 500 is deployed toprovide flexibility. Furthermore, the laser module may have specificoptical and electrical connectors to optically couple the optoelectroniccomponents 506 to the optical chips 502 and/or to electrically couplethe optoelectronic components 506 to corresponding electrical components(e.g., driver circuits, etc.).

The disclosed configurations include highly integrated photonictransceiver assembly and packaging configurations that may eliminatewire bonds, provide mechanical integrity, power and signal integrity,superior thermal performance, supports the use of LGA/BGA sockets ifnecessary, and/or permits yielded assembly of optical components to beco-packaged with electrical components. Furthermore, the disclosedembodiments include assembly and packaging configurations that may beused as an alternative to multi-chip solutions that use wirebonding orthru substrate vias (TSV) for electrical connection.

The disclosed assembly and packaging configurations may improve signalintegrity, power integrity, thermal performance, optical couplings, andprovide removable components of improved reliability and serviceability.

With respect to signal integrity, the disclosed embodiments providecontrol of electrical couplings that results in relatively low parasiticelectrical interconnects through face to face EIC/OIC coupling andflip-chip OIC to interposer coupling. Such electrical couplings may beradio frequency RF couplings which may require relatively tighttolerances for suitable performance, and the disclosed embodimentspermit control of tolerances to maintain suitable RF performance.

The disclosed configurations may also improve power integrity, which maybe relevant in high speed complementary metal-oxide-semiconductor (CMOS)integrated circuit configurations. Multiple parallel optical channelsmay include components such as retimers, equalizers, Mach-Zehndermodulator drivers, electro-absorption modulators, optical ring drivers,transimpedance amplifiers, or other components which may produce largesupply dynamic currents. Transimpedance amplifiers, equalizers, andretimers may be sensitive to electrical supply ripples and ground noiseand therefore may benefit broadband low impedance power distributionnetworks both on chips and off-chips. The flip-chip packaging approachdescribed herein results in a suitable power supply and grounddistribution.

The disclosed embodiments improve thermal performance because the highlyintegrated high speed electronic components dissipate heat in a fairlysmall footprint as a result of the EIC being stacked on the siliconphotonic OIC. Using flip-chip couplings for the stacked EIC/OIC, thelarger IC may be configured to be in contact with a Thermal InterfaceMaterial (TIM) and/or a heat sink, thus acting as a heat spreader. Forexample, a 500 μm thickness of TIM with a k of 6 W/(m·K) on the back ofa 20×25 mm photonic OIC will add another 50/(6e−3*(20*25)/0.5)=9 deg C.instead of 30 deg C. if the TIM was on the back of the EIC (if the EICis 11×12 mm). Such differences in heat dissipation may be important forreliability and performance of the ICs, particularly when othertemperature-sensitive components such as semiconductor lasers areincluded in a package.

The disclosed configurations may permit optical fiber array attachmentto be one of the last step assembly steps and may provide the ability touse pigtailed and/or connectorized optical interfaces. Standardizedpackaging configurations may be used to assemble the silicon photonicstack for OIC. Active optical interface attachment may be performedlast, thereby avoiding optical epoxies to be exposed to the elevatedtemperatures typically found in reflow processes. The disclosedpackaging and assembly configurations may also provide a mechanicalplatform on which to attach the fiber array or connector which would notbe present if the stack was mounted “stack up” using wirebonds or TSVson an electronic substrates.

The disclosed configurations also permit components to be removed, whichin turn may improve reliability and serviceability. High speed LGAsockets or interposers may be implemented to offer removable opticalinterfaces. Such configurations may include benefits for componenttesting, reworking, yields etc. Without this removability advantage, aco-packaged optoelectronic solution may suffer from serviceabilitydisadvantages. In addition, the removable optics configurationsdescribed herein may permit pluggable optoelectronic modules to be usedin switch ASIC co-packaged optics and silicon photonic assemblies.

As mentioned above, the disclosed embodiments include packagingconfigurations that may be used as an alternative to thru substrate vias(TSV). However, the concepts described herein may also be implementedwith configurations that include TSVs. FIGS. 6A-6B include examples ofconfigurations that include TSVs that may be implemented according tothe concepts described herein.

FIGS. 6A-6B are side cross-sectional views of examples optoelectronicmodules. FIG. 6A illustrates an optoelectronic module 600 and FIG. 6Billustrates an optoelectronic module 650.

The optoelectronic module 600 includes an interposer 602, and EIC 604,and an OIC 606. In the illustrated configuration, the EIC 604 ispositioned over and coupled to the interposer 602, and the OIC 606 ispositioned over and coupled to the EIC 604. Similar configurations areshown and described in FIGS. 1 and 2A-2F, which also include EICspositioned between corresponding interposers and OICs. As illustrated,the EIC 604 may include TSVs 608. The TSVs 608 may extend through theEIC 604 and may electrically couple the EIC 604 with other components.In particular, the TSVs 608 may electrically couple the interposer 602and the OIC 606. The interposer 602 may include vias 610. The vias 610may extend through the interposer 602 and may electrically couple theinterposer 602 with other components. In particular, the vias 610 mayelectrically couple the EIC 604 with external components, such as anMCM. Accordingly, the interposer 602 may include pads 612 which may beelectrically coupled to corresponding electrical couplings of a socketof an MCM (see, for example, FIG. 3 and associated description)

In the configuration of FIG. 6A, the OIC 606 and the EIC 604 may beelectrically and mechanically coupled to one another, the resultingstack may be flipped and the EIC 604 may be electrically andmechanically coupled to the interposer 602, similar to theconfigurations described with respect to the FIGS. 2A-2F.

FIG. 6B includes an alternative configuration of an optoelectronicmodule 650, which includes an OIC 656 positioned between an EIC 654 andan interposer 652. In the illustrated configuration, the OIC 656 ispositioned over and coupled to the interposer 602, and the EIC 654 ispositioned over and coupled to the OIC 656. Accordingly, in suchconfigurations the position of the OIC 656 and the EIC 654 are switchedwhen compared to the configuration of the optoelectronic module 600 ofFIG. 6A.

In the configuration of FIG. 6B, the OIC 656 includes TSVs 658, ratherthan the EIC 654. The TSVs 658 may extend through the OIC 656 and mayelectrically couple the EIC OIC 656 with other components. Inparticular, the TSVs 658 may electrically couple the interposer 652 andthe EIC 654. The interposer 652 may include vias 660. The vias 660 mayextend through the interposer 652 and may electrically couple theinterposer 652 with other components. In particular, the vias 660 mayelectrically couple the OIC 656 with external components, such as anMCM. Accordingly, the interposer 652 may include pads 662 which may beelectrically coupled to corresponding electrical couplings of a socketof an MCM (see, for example, FIG. 3 and associated description)

In the configuration of FIG. 6B, the OIC 656 and the EIC 654 may beelectrically and mechanically coupled to one another, and the resultingstack may be electrically and mechanically coupled to the interposer652, with the OIC 656 positioned between the EIC 654 and the interposer652.

In the configurations of FIGS. 6A and 6B, the interposers 602, 652 mayprovide mechanical support for the OIC/EIC stacks, which may make theresulting optoelectronic modules 600, 650 easier to assembly. This inturn may be useful for large chip packaging configurations (e.g., MCMs)and co-packaged optics configurations, such as those described above. Inaddition, the disclosed configurations may result in improved signalintegrity, power integrity and thermal dissipation.

FIG. 7 is a perspective view of another example of an optoelectronicmodule 700. The optoelectronic module 700 may include any suitableaspects described with respect to the optoelectronic module 200 of FIGS.2A-2F and 3 , and similar components are indicated with similarnumbering.

As explained above, the optoelectronic module 200 may include alignmentfeatures for alignment. In FIGS. 2A-2F and 3 , the optoelectronic module200 includes the alignment features 224 on the optical connector 216 andthe alignment features 226 on the interposer 202, although otherconfigurations may be implemented. FIG. 7 illustrates another exampleconfiguration with alignment features 724 on the optical connector 216and corresponding alignment features 726 on the interposer 202 andalignment features 727 on the AMC 220.

While the configuration of FIGS. 2A-2F and 3 includes alignment features224, 226 on the optical connector 216 and the interposer 202, theconfiguration of FIG. 7 includes the alignment features 727 on the AMC220 in addition to the alignment features 724 on the optical connector216 and the alignment features 726 on the interposer 202. In suchconfigurations, the alignment features 724 and the alignment features726, 727 may permit the optical connector 216, the interposer 202, andthe AMC 220 to be aligned and/or coupled to one another. In particular,the alignment features 724, 726, 727 may permit the optical connector216 and/or the AMC 220 to be moved with respect to the interposer 202 inone direction (or vice versa, where the interposer 202 may be moved withrespect to the optical connector 216 and/or the AMC 220), whilerestricting movement in other directions.

In the illustrated configuration, the alignment features 724 are pins(e.g., round pins) attached to the optical connector 216. The alignmentfeatures 726 are v-shaped grooves defined the body of the OIC 208 andthe alignment features 727 are v-shaped grooves defined in the body ofAMC 220. The v-shaped grooves may be sized and shaped to receive thepins thereby resulting in higher precision and better optical alignmentof the components with respect to one another. As shown, the alignmentfeatures 726 on the interposer 202 may be oriented opposite or upsidedown with respect to the alignment features 727 on the AMC 220.

The alignment features 724 may be sized and shaped to extend through thealignment features 727 on the AMC 220 into the alignment features 726 onthe interposer 202. Thus, the alignment features 724 are sized andshaped to mate with and be received in the alignment features 726, 727.However, this configuration is another example of mating alignmentfeatures. Any other suitable mating alignment features may beimplemented on the optical connector 216, the interposer 202 and/or theAMC 220. The pin and groove configuration of the alignment feature 224,and alignment features 726, 727 may restrict movement in two directions(e.g., X and Y) while permitting movement in a third direction (e.g, Z).However, other configurations may be implemented that permit additionalrange of motion. For example, slots, rips or holes may be implemented topermit movement in two direction (e.g., Z and X) while restrictingmovement in one direction (e.g., Y). In some circumstances, theoptoelectronic module 200 may be powered up to optically align theoptical components to one another.

In one non-limiting example, an optoelectronic module may include astack assembly including an electrical integrated circuit and an opticalintegrated circuit electrically and mechanically coupled to one another,an interposer electrically and mechanically coupled to the stackassembly, and an optical connector to optically couple the opticalintegrated circuit with an array of optical fibers.

The interposer may define a recess and the electrical integrated circuitof the stack assembly may be positioned at least partially within therecess. An adiabatic mode converter may be positioned between theoptical connector and the interposer. The adiabatic mode converter maybe positioned at least partially in a recess defined by the interposer.The recess may be sized and shaped to receive the adiabatic modeconverter.

The interposer may include a first alignment feature that corresponds toa second alignment feature of the optical connector. The first alignmentfeature and the second alignment feature may restrict movement of theoptical connector with respect to the interposer in two directions whilepermitting movement in a third direction.

The optoelectronic module may include an adiabatic mode converterpositioned between the optical connector and the interposer, a firstalignment feature included on the interposer, a second alignment featureincluded on the optical connector, and a third alignment feature on theadiabatic mode converter The first alignment feature, the secondalignment feature, and third alignment feature may be configured toengage one another to align the interposer, the optical connector, andthe adiabatic mode converter.

The electrical integrated circuit and the optical integrated circuit maybe face to face bonded to one another. The stack assembly and theinterposer may be flip-chip bonded to one another. The opticalintegrated circuit may be an integrated silicon photonic circuit. Thestack assembly may be a silicon photonic stacked die.

A multiple chip module may include a substrate, a plurality of socketspositioned on the substrate. The optoelectronic module described hereinmay be positioned in one of the sockets. An integrated circuit may routeelectrical signals to the optoelectronic module.

In another example, a method may include face to face bonding anelectrical integrated circuit and an optical integrated circuit to oneanother to form a stack assembly. The method may include flip-chipbonding the stack assembly to an interposer. The method may includeoptically coupling the optical integrated circuit with a fiber array viaan optical connector. The method may include mechanically coupling theoptical connector to the interposer.

The method may include positioning the optical integrated circuit in arecess defined by the interposer. The method may include positioning aportion of the optical connector in the recess defined by theinterposer. The method may include positioning an adiabatic modeconverter in a recess defined by the interposer. The adiabatic modeconverter may be optically coupled between the optical integratedcircuit and the optical connector. The method may include mating a firstalignment feature of the optical connector with a second alignmentfeature of the interposer to align the optical connector with theinterposer. The first alignment feature and the second alignment featuremay restrict movement of the optical connector with respect to theinterposer in two directions while permitting movement in a thirddirection.

The method may include mating a first alignment feature of the opticalconnector with a second alignment feature of the interposer and thirdalignment feature of an adiabatic mode converter, to align the opticalconnector with the adiabatic mode converter and the interposer.

Mechanically coupling the optical connector to the interposer may forman optoelectronic module, and the method may further include positioningthe optoelectronic module in one of a plurality of sockets of a multiplechip module.

Unless specific arrangements described herein are mutually exclusivewith one another, the various implementations described herein can becombined to enhance system functionality or to produce complementaryfunctions. Likewise, aspects of the implementations may be implementedin standalone arrangements. Thus, the above description has been givenby way of example only and modification in detail may be made within thescope of the present invention.

With respect to the use of substantially any plural or singular termsherein, those having skill in the art can translate from the plural tothe singular or from the singular to the plural as is appropriate to thecontext or application. The various singular/plural permutations may beexpressly set forth herein for sake of clarity. A reference to anelement in the singular is not intended to mean “one and only one”unless specifically stated, but rather “one or more.” Moreover, nothingdisclosed herein is intended to be dedicated to the public regardless ofwhether such disclosure is explicitly recited in the above description.

In general, terms used herein, and especially in the appended claims(e.g., bodies of the appended claims) are generally intended as “open”terms (e.g., the term “including” should be interpreted as “includingbut not limited to,” the term “having” should be interpreted as “havingat least,” the term “includes” should be interpreted as “includes but isnot limited to,” etc.). Furthermore, in those instances where aconvention analogous to “at least one of A, B, and C, etc.” is used, ingeneral, such a construction is intended in the sense one having skillin the art would understand the convention (e.g., “a system having atleast one of A, B, and C” would include but not be limited to systemsthat include A alone, B alone, C alone, A and B together, A and Ctogether, B and C together, or A, B, and C together, etc.). Also, aphrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to include one ofthe terms, either of the terms, or both terms. For example, the phrase“A or B” will be understood to include the possibilities of “A” or “B”or “A and B.” The present invention may be embodied in other specificforms without departing from its spirit or essential characteristics.

The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. An optoelectronic module, comprising: a stackassembly including an electrical integrated circuit and an opticalintegrated circuit electrically and mechanically coupled to one another,the optical integrated circuit comprising a first array of electricalcouplings positioned around the electrical integrated circuit on a firstface of the optical integrated circuit; an interposer electrically andmechanically coupled to the stack assembly via the first array ofelectrical couplings and a second array of electrical couplingspositioned around a first recess formed in a first face of theinterposer; an adiabatic mode converter positioned in a second recessdefined in a side of the interposer, the first recess being separatedfrom the second recess by a portion of the interposer underlying thesecond array of electrical couplings; and an optical connectorpositioned in the second recess and configured to optically couple theoptical integrated circuit with an array of optical fibers, wherein theelectrical integrated circuit extends at least partially within thefirst recess of the interposer.
 2. The optoelectronic module of claim 1,wherein the first face of the optical integrated circuit and the firstface of the interposer are adjacent with the first array of electricalcouplings and the second array of electrical couplings in between. 3.The optoelectronic module of claim 1, wherein the adiabatic modeconverter is positioned between the optical connector and theinterposer.
 4. The optoelectronic module of claim 1, wherein theinterposer includes a first alignment feature that corresponds to asecond alignment feature of the optical connector.
 5. The optoelectronicmodule of claim 4, wherein the first alignment feature and the secondalignment feature restrict movement of the optical connector withrespect to the interposer in two directions while permitting movement ina third direction.
 6. The optoelectronic module of claim 1, furthercomprising: a first alignment feature included on the interposer; asecond alignment feature included on the optical connector; and a thirdalignment feature on the adiabatic mode converter, wherein the firstalignment feature, the second alignment feature, and third alignmentfeature are configured to engage one another to align the interposer,the optical connector, and the adiabatic mode converter.
 7. Theoptoelectronic module of claim 1, wherein the electrical integratedcircuit and the optical integrated circuit are face-to-face bonded toone another.
 8. The optoelectronic module of claim 1, wherein the stackassembly and the interposer are flip-chip bonded to one another.
 9. Theoptoelectronic module of claim 1, wherein the optical integrated circuitis an integrated silicon photonic circuit.
 10. The optoelectronic moduleof claim 1, wherein the stack assembly is a silicon photonic stackeddie.
 11. A multiple chip module comprising: a substrate; a plurality ofsockets positioned on the substrate, the optoelectronic module of claim1 positioned in one of the sockets; and an integrated circuit to routeelectrical signals to the optoelectronic module.
 12. The optoelectronicmodule of claim 1, wherein the adiabatic mode converter comprises analignment feature configured to align the interposer, the opticalconnector, and the adiabatic mode converter.
 13. The optoelectronicmodule of claim 1, wherein the adiabatic mode converter is positionedagainst the optical integrated circuit.
 14. The optoelectronic module ofclaim 1, the second recess is sized and shaped to receive an entirety ofthe adiabatic mode converter.
 15. An optoelectronic module, comprising:an optical integrated circuit comprising a first array of electricalcouplings on a first face of the optical integrated circuit; aninterposer coupled to the optical integrated circuit via the first arrayof electrical couplings and a second array of electrical couplingspositioned around a first recess formed in a first face of theinterposer; an adiabatic mode converter positioned within a secondrecess defined in a side of the interposer, the first recess beingseparated from the second recess by a portion of the interposerunderlying the second array of electrical couplings; and an opticalconnector positioned in the second recess adjacent to the adiabatic modeconverter, wherein the first face of the optical integrated circuit andthe first face of the interposer are adjacent with the first array ofelectrical couplings and the second array of electrical couplings inbetween.
 16. The optoelectronic module of claim 15, further comprisingan electrical integrated circuit electrically coupled to the opticalintegrated circuit, wherein the electrical integrated circuit ispositioned at least particularly within the first recess formed in thefirst face of the interposer.
 17. The optoelectronic module of claim 16,wherein the electrical integrated circuit and the optical integratedcircuit are face-to-face bonded to one another to form a stack assembly,and wherein the stack assembly and the interposer are flip-chip bondedto one another.
 18. The optoelectronic module of claim 15, the secondrecess is sized and shaped to receive an entirety of the adiabatic modeconverter.
 19. An optoelectronic module, comprising: a stack assemblyincluding an electrical integrated circuit and an optical integratedcircuit face-to-face bonded to one another; an interposer flip-chipbonded to the stack assembly via a first array of electrical couplingspositioned on a first face of the optical integrated circuit and asecond array of electrical couplings positioned on a first face of theinterposer, the electrical integrated circuit being positioned to extendat least partially within a first recess formed in the first face of theinterposer; an adiabatic mode converter positioned in a second recessdefined in a side of the interposer; and an optical connector having atleast a portion positioned in the second recess defined in the side ofthe interposer, wherein the first recess is separated from the secondrecess by a portion of the interposer underlying the second array ofelectrical couplings.
 20. The optoelectronic module of claim 19, whereinthe adiabatic mode converter is positioned against the opticalintegrated circuit.
 21. The optoelectronic module of claim 19, whereinthe second recess is sized and shaped to receive an entirety of theadiabatic mode converter.